This is the second episode in which I noticed something odd slipped in...
Around 40 minutes into the episode, Ethan asks if they can watch Donald Duck, and Isaac replies "My dad loves that."
He's looking at Ethan when he says it, clearly addressing him.
Why wouldn't he just say "dad"? And wouldn't Ethan already know that, having grown up in the same household?
ETA: Perhaps he was speaking indirectly to Olivia, since Ethan turns to her.
However, a similar thing happened in the third episode, after the confrontation between Ethan, Olivia and the parents.
Lydia runs off and is praying, and shortly afterwards, when it's just Lydia, Moriah, Micah and Isaac together, Micah says "How do you feel about, like, my parents not letting Ethan and Olivia hang out with their siblings?"
Why would he say "my parents" if he's talking to his own siblings?
Is this a blended family? Are some adopted? Foster children? Seems like a weird choice of words when referring to their own family members.